American Journal of Applied Science and Technology
20
https://theusajournals.com/index.php/ajast
VOLUME
Vol.05 Issue 04 2025
PAGE NO.
20-22
10.37547/ajast/Volume05Issue04-04
Description of Measurements of Foaming Intensity
During Amine Purification of Natural Gases from Acidic
Components
Eshdavlatova Gulrukh Eshmamatovna
Associate Professor of Karshi State Technical University, Uzbekistan
Turabayeva Nargisа Bekmuradovna
Senior Lecturer Karshi State Technical University, Uzbekistan
Received:
19 February 2025;
Accepted:
18 March 2025;
Published:
21 April 2025
Abstract:
In this article, the method for measuring the intensity of foaming of an inhibitor in a diethanolamine
solution is based on passing gas through an aqueous solution of amine in a bubbler at a certain speed for a certain
time and measuring its foaming characteristics. The stability time and foam quenching time in the amine solution
are determined. The effect of the defoamer on the intensity of foaming is studied.
Keywords:
Diethanolamine, regeneration, gas purification, foaming, defoamer, bubbling, foam height, foam
quenching, block polymer alkylene oxide.
Introduction:
Absorption is one of the most popular methods for
cleaning natural gases from acidic components (H2S
and CO2). However, the absorption process often
encounters various operational problems, including
foaming. The main objective of this work is to
determine the influence of various causes on foaming
in a DEA solution and to evaluate the foam-fighting
properties of the EG1951E antifoam agent based on an
alkylene oxide block polymer.
The need to extract acidic components (H2S and CO2)
from a natural gas stream is determined by their ability
to exhibit corrosive activity in the presence of water,
especially at high temperatures, as well as the
formation of carbon dioxide crystal hydrates in a
methane extraction unit.
METHODOLOGY
The process of cleaning natural gas from H2S and CO2
impurities is carried out by the method of selective
absorption (chemical absorption) of acidic components
by an absorbent liquid, therefore, the absorbed
substances pass from the gas mixture into the liquid
absorber, forming chemical compounds [1].
As a result of the interaction of gaseous substances H2S
and CO2 with a solution of diethanolamine in the liquid
phase, the following reactions occur:
R
2
HN + H
2
S ↔ [R
2
NH
2
] HS ↔ [R
2
NH
2
]
+
+ HS
-
R
2
HN + СО
2
+ Н
2
О ↔ [R
2
NH
2
] НСО
3
↔ [R
2
NH
2
]
+
+ HCO
3
-
here, R- is the radical
–
CH2CH2OH
However, the use of amine solutions in the purification
of acidic components has its drawbacks. One of the
important drawbacks is the strong foaming of this
absorbent. This leads to overconsumption of the
absorbent as a result of its entrainment with the
purified gas, simultaneously worsening the level of
purification from acidic components and reducing the
productivity of the plant.
Foaming of amines is a complex problem caused by the
presence of various surfactants in the amine solution,
so combating it is an urgent task in improving the
process of purification of natural gas from acidic
components.
The research was conducted and the results were
summarized at the Shurtan Gas Chemical Complex.
Obstacles in the technology of amine solution
American Journal of Applied Science and Technology
21
https://theusajournals.com/index.php/ajast
American Journal of Applied Science and Technology (ISSN: 2771-2745)
purification were identified and the influence of
mechanical impurities of various origins on foam
formation was studied. The defoaming ability of
various imported and domestic defoamers was studied.
RESULTS
Defoamers replace foaming agents between the gas
and liquid phases, where they form a water-
impermeable surface film and increase surface tension.
They must be insoluble in the added liquids. Defoamers
have the same composition, the same chemical
structure and a similar mechanism of action as
defoamers. They also form a thin film between the gas
and liquid phases, thereby eliminating gas bubbles. In
this case, the surface area is reduced and the system
becomes thermodynamically more stable [2-3].
A block polymer defoamer containing alkylene oxides is
described, which can be obtained by polymerizing
alkylene oxide in the presence of an organic initiator to
form the said polymer. It was found that such block
polymers have improved foam suppression properties
while maintaining their biodegradable properties. To
date, studies on the removal of acidic components and
the foaming behavior of DEA solution are still
insufficient. In addition, studies of antifoam properties
in absorption processes using DEA are more limited.
Therefore, the objective of this study is to investigate
the effect of decomposition products on foaming in a
30-33% DEA solution by weight and to evaluate the
defoaming properties of EG1951E defoamer based on
alkylene oxide block polymer at different operating
temperatures and gas flow rates. At the Shurtan Gas
Chemical Complex, during amine purification of natural
gases from acidic components, the highest absorption
of H2S and CO2 was found in a 30-33% DEA solution.
Therefore, in this study, different defoamers were used
for 30-33% DEA solution [4].
The main patterns of the influence of various
substances on the process of foaming of amine solution
in natural gas purification plants were obtained and an
experimental assessment of the influence of the quality
of the initial absorbent on its foaming was carried out
under laboratory conditions (according to the standard
KSt 39.2-22:2008).
Measurement procedure: assemble a setup from
sequentially connected filters, a glass bubbler with a
glass porous plate. Then pour regenerated 30-33% DEA
amine solution into the bubbler in such quantity that
the height of the solution was (20-25) mm
(approximately 200 ml). The nitrogen flow rate was set
to 4 dm3/h using the rheometer and the bubbler was
connected. The solution was bubbled through the
diffuser for 3-5 min until stable foam was formed to
obtain the final foam height. Then the nitrogen gas
supply was turned off and the foam destruction time
was measured. The foam height is taken as the
difference between the height of the foamed liquid and
the height of the initial solution. Again, 200 ml of the
test solution was poured into the bubbler and the
measurements were repeated. The measurements
were repeated at least three times. The experiment
was also repeated with a saturated DEA solution.
DISCUSSION
Under laboratory conditions, tests of Nalco EC9055A
and EG1951E antifoams based on alkylene oxide block
polymer were conducted to compare their efficiency in
preventing foaming during amine purification of
natural gases. The density of the DEA solution was
measured at various temperatures in the range from 20
°C to 40 °C, using an AON-1 hydrometer GOST 18481-
811 (Ukraine, size from 1000 to 1060 / 1060 to 1120).
The results are shown in the table below.
Name of the indicator
Nalco EC9055A
EG1951E
Saturated
solution
DEA
Regenerat
ed
solution
DEA
Saturated
solution
DEA
Regenerat
ed
solution
DEA
Solution density, g/cm
3
1,111
1,054
1,111
1,054
Defoamer concentration (at
20 °C), g/ml
0,31
0,29
0,31
0,29
pH of the tested solution
10,3
10,4
10,3
10,4
Foam height (at 5 s), mm
30
26
22
18
Foam height (at 15 s), mm
48
51
40
42
American Journal of Applied Science and Technology
22
https://theusajournals.com/index.php/ajast
American Journal of Applied Science and Technology (ISSN: 2771-2745)
Foam quenching time (at 20
°C), s
20
25
12
10
The method consists of introducing a polymer alkylene
oxide liquid (EG1951E), EO - PO, into an absorbent.
EG1951E is introduced into an absorption solution with
a pH of 9.5-10.5. The results of a study of the selectivity
of acid gas absorption by a DEA solution with the
addition of 0.14% defoamer showed a higher selectivity
of EG1951E compared to Nalco EC 9055A [6].
CONCLUSION
Based on the positive results of laboratory
experiments, a new defoamer EG1951E based on block
polymer alkylene oxide was proposed and introduced
into the amine purification of natural gas from acidic
components for the first time at the Shurtan Gas
Chemical Complex. Due to the introduction of the
proposed defoamer, the degree of foaming was
reduced by 2.5 times.
Field testing has shown that EG1951E alkylene oxide
block polymer defoamer is more effective than Nalco's
previous defoamer, EC 9055A, in preventing foaming
during amine scrubbing of natural gas to remove sour
components.
REFERENCES
Ильина Е.Н., Клямер С.Д. Извлечение сероводорода
и углекислоты из природного газа и производство
элементарной серы. М.,:БНИИЭГазпром,1969.
-86
с.3» NG/LNG/SNG Rectisol Haudbook. Hydrocarbon
Processing, 1973, vol. 52, 4, p.98.
Рябова T.C., Чемодуров П.А. Очистка природного
газа от сероводорода. М.:ВНМИГазпром, 1975.
-
40 с.
Эшдавлатова Г.Э., Камалов Л.С., Достижение
высокой селективности при аминовой очистке
природных газов // QarDU XABARLARI. Ilmiy
-nazariy,
uslubiy jurnal. 2024 1/2. 95-100 c.
Эшдавлатова Г.Э., Камалов Л.С. ОПРЕДЕЛЕНИЕ
КОЛИЧЕСТВА УГЛЕКИСЛОГО ГАЗА В РАЗЛИЧНЫХ
ЕДИНИЦАХ В АМИННЫХ РАСТВОРАХ. UNIVERSUM:
ТЕХНИЧЕСКИЕ НАУКИ. Выпуск: 10(127). Октябрь
2024. Часть 4. 55
-
58 с. Москва
Eshdavlatova G.E., Kamolov L.S. Tabiiy gazlarni nordon
komponentlardan aminli tozalashda ko‘piklanish
s
abablari va uning intensivligiga ta’sir etuvchi omillar.
ФАН ВА ТЕХНОЛОГИЯЛАР ТАРАҚҚИЁТИ ИЛМИЙ –
ТЕХНИКАВИЙ ЖУРНАЛ. 2025/1. 61
-
64 б. Buxoro.
Г.Э.Эшдавлатова,
Л.С.Камолов.
ОПИСАНИЕ
ИЗМЕРЕНИЙ ИНТЕНСИВНОСТИ ПЕНООБРАЗОВАНИЯ
ПРИ АМИННОЙ ОЧИСТКЕ ПРИРОДНЫХ ГАЗОВ ОТ
КИСЛЫХ
КОМПОНЕНТОВ.
Композиционные
материалы. Узбекский Научно
-
технический и
производственный журнал. №3/2024. 172
-174 c.
